The purpose of the research is the definition of the abnormalities of cellular immunity which occur after operative and accidential trauma and burns. We will study human subjects and an animal model in order to define relationships between circulating immunosuppressive polypeptide factor(s), diminished peripheral blood lymphocyte responsiveness to mitogenic stimulation and the presence of suppressor cells. We will also look for a correlation between the results of these in vitro tests or immunological impairment with in vivo manifestations of anergy, sepsis and mortality.